Toyota Repair: P0446

Question
Working on a friends 2001 Corolla. Im a fairly competent DIY-er Periodically on his car P0446 comes up. Use my basic OB 2 code reader. Since we don't have the emissions regs in our area just reset it but think it's time to further exam it. Cap is still original but still seems good(?). Trying to find problem and hopefully( maybe not) save replacing the vapor canister. Noticed that when the gas cap is removed no pressure is released. Would that be the VSV at the canister? Is that also the same as the "purge solenoid(Vent Valve)? Are these accurate assumptions. Or will this have to go to dealer.

Answer
A purge VSV malfunction should give you a P0441 code, since you are only getting the P0446 which is a leak at the tank and it's associated VSVs and hoses, the canister may be the cause, it is also very common for the fuel cap not holding pressure to be the reason, remove the fuel cap and inspect the filler neck area on top for any damage, try replacing the fuel cap with an OEM part or equivalent, clear the code and see if it comes back